The invention relates to an apparatus and a process for the production of a device for detaching portions from workpieces in plate, sheet or leaf form, in particular sheets of cardboard which are used in folding box industry and which each contain at least one blank for a folding box or the like and adjoining waste pieces, wherein the latter are moved out of the plane of the sheet of cardboard or the like by means of a breaking-out tool.
The production of folding boxes primarily involves dealing with sheet material of cardboard. In an operation which is known as sheet laying-out, depending on the size of the sheet and the folding box, one or more blanks or utilizable portions are produced in the sheet of cardboard or the like. At any event waste areas or waste portions occur, adjoining the blanks and separated therefrom by desired-separation lines. Efforts are made to position the blanks in the sheet laying-out operation relative to each other in such a way that the amount of waste produced is as small as possible; it will be appreciated moreover that the amount of waste produced also differs when dealing with different blanks.
After the sheet laying-out operation, the sheet material is continuously stamped and grooved in an automatic flat stamping apparatus, that is to say, the fold lines, bend lines and desired-separation lines are formed or impressed in the sheet material. The waste is then broken out by means of breaking-out tools which engage the waste portions at both sides thereof by means of pressure elements, which clampingly hold such a waste portion and which for example draw it out of the plane of the sheet of material.
Breaking-out tools of that kind are known for example from German published specification (DE-AS) No 85 759; the waste portion is pushed by means of a plate which is moved perpendicularly thereto, out of the sheet of cardboard on to the head of a stem which is disposed resiliently therebeneath, and is ejected by same. Such a device is comparatively complicated and expensive, especially as a sheet laying-out operation not infrequently necessitates the use of one hundred to two hundred individual breaking-out tools. In addition to that high level of capital investment, there is also the disadvantage that the operation of setting the breaking-out tools on a setting table outside the machine which performs the breaking-out operation is to be considered extremely time-consuming.
Similar disadvantages are suffered in a breaking-out apparatus which has two rollers which rotate on both sides on the sheet of cardboard, one thereof carrying radial breaking-out pins, in accordance with German published specification (DE-AS) No 16 11 617.
In the folding box industry, orders recur frequently so that as many lay-outs as possible are retained in order to avoid incurring long setting-up times. For that purpose, the recurrent orders, breaking-out boards with nails which are driven in by hand have long been used as the breaking-out tool, the breaking-out board being screwed fast to the upper tool frame of the machine. That is a highly inaccurate method which results in frequent disorders in the automatic stamping machine.
Having regard to those factors, the inventor set himself the aim of improving an apparatus of the kind set forth in the opening part of this specification, and ensuring simple and inexpensive breaking-out, with a high-level of operating reliability.